The subject of the present invention is a multi-lobed, double-wall inflatable vault, only the volume of air included between the two walls of which is pressurized, thus leaving the space which the vault covers at ambient pressure.
Generally, such an inflatable vault comprises a plurality of longitudinal beams arranged side by side, means of sliding at least one longitudinal end of each of the beams along at least one deployment or folding path and means for supplying the beams with inflation fluid.
This type of vault is designed in order, inter alia, to permit its deployment by means of simple inflation, as well as its retraction by deflation, which makes it possible, as desired, to cover a space for the purpose of protecting it from bad weather and for uncovering it in fine weather.
Such a vault may be used for temporarily covering large-size installations, such as stadia with stands for spectators. Such a vault represents an enormous surface area of fabric, weighing from 50 to 100 tonnes, which is impossible to produce in a factory, to transport and to install as a single completely finished assembly. However, if the vault is produced as several elements, it is advisable, on the one hand, for such elements to be totally completed, tested in the factory, particularly to check their leaktightness, and, on the other hand, for the assembly of such elements together to be easy, rapid and to require no costly site equipment.
Vaults of this type are already known, in which deployment and retraction can be produced by means of simple inflation and deflation, in which only the space between the two walls is pressurized and which are described, particularly, in patents FR-A-2,166,397 and FR-A-2,326,544.
Patent FR-A-2,166,397 relates to an inflatable structure including a succession of inflatable box structures which bear on one another when they are inflated and which are placed between two sheets to which they are fastened, such sheets being stretched by the box structures on inflation of the structure. Given the design of this structure, it cannot be applied to large-size constructions which is one of the objectives which the present invention proposes to achieve.
Patent FR-A-2,326,544 relates to an inflatable flexible structure consisting of a nave with at least two walls, which can be deployed and folded or retracted, composed of a series of contiguous chambers which can be flattened and pressurized, the dividing walls of which space apart outer and inner, and, optionally median, walls of the nave. The multiple elements making up the vault are thus simple elementary panels of leaktight fabric which must be assembled on site in order to produce continuous links which are both strong and leaktight over great lengths. This requires very precise manufacturing tolerances and considerable involved assembly operations on site, which does not guarantee the total reliability of the product obtained.
An inflatable vault is also known from patent FR-A-2,621,944, in which each beam includes two opposite panels forming flanges and each constituting one of the lobes of inner or outer wall of the vault and two lateral panels forming webs of the beam.
Equivalent panels of adjacent beams are connected together with the aid of discontinuous mechanical linking means comprising, on the one hand, a series of flaps extending the panels of each beam along at least one of their longitudinal edges and, on the other hand, a plurality of profiled sections slipped one behind the other, simultaneously from one end to the other of each of the flaps to be joined.
Such linking means pose problems owing to the fact that each beam is composed of at least two independent panels, the corresponding flaps of which must be inserted in the profiled sections at the same time as the flaps of the panels of the adjacent beam, and this has to be done over the entire length of the beams.